Puberty is the beginning of adolescence. But when is
puberty,
exactly? The hormonal changes begin as early as 8 years
old.
But the physical changes don't usually make themselves known for
several
years later.

In modern western societies, we usually say that puberty starts
between
11 and 12 years old for girls, and between 12 and 13 for boys.
95%
of all girls will start somewhere between 8 1/2 and 13, and 95% of boys
a year
or more later, between 9 1/2 and 15.

The first clear sign of puberty for girls is the beginnings of
breast
development, around the age of 12. There is also an overall growth
spurt
that begins around 10 1/2, peaks at 12, and begins to slow around
14.
But the main mark of puberty is menarche (pronounced
MEN-ark-ee),
the first period. In modern western societies, it tends to
happen between 12 and 13.

Curiously, in 1890, a girl's first period tended to occur at 14 or
15.
In 1840, it often began as late as 17! It is thought that these
variations were
primarily due to differences in nutrition. Also notice that the
average age at
which a woman marries today is around 25. In 1890, it was around
22. In the Middle Ages, it could be as young as 12 or 14.
(Remember
that Romeo and Juliet were only 16!)

The first mark of puberty in boys is the start of testes growth
around
the age of 13, and penis growth around 14. The growth spurt for
boys
tends to begin at 12 1/2, peak at 14, and slows by 16 - hence the
common
sight of girls towering over their partners at school dances!

The growth spurt we mentioned is about 8 to 10 cm (3 to 4
inches)
of height a year for both girls and boys - similar to the rate of
growth
back when they were only 2 years old! With this spurt, there is a
significant loss of fat in boys, especially in the limbs, which
accounts
for the common "beanpole" look among adolescents. Girls may also
lose fat, but not as dramatically as boys. An unfortunate
tendency
today, however, is the onset of obesity in adolescence due to the high
fat, high sugar diet many teens adopt.

Adolescence is definitely a time of increasing strength: A 14
year old boy has 14 times the muscle cells of a 5 year old boy. A
14 year old girl has 10 times the muscle cells of a 5 year old girl.

Psychologically, adolescence is a pretty busy time. Becoming a
sexual adult involves a number of things that may very well have
instinctual
roots: Boys compete with each other for attention by shows of
physical
ability and acts of daring, often bordering on the insane; girls
compete
for the attention of boys, most commonly by attempting to enhance their
appearance. Different cultures have different details, but the
pattern
is pretty universal.

Ruffino, Sean, and Carol Ann

The single most important thing seems to be social acceptance.
If you do not have a circle of friends, in the teenage world you are
nothing.
For many teenagers, whether their isolation is due to a family move or
social inhibition, physical abnormalities or not meeting local
standards
of attractiveness, not being accepted is a cause of depression and
sometimes
suicide. I believe this response is very likely one we have
inherited
from our very social pre-human ancestors: No group, and you might
as well be dead.

In later adolescence, two things dominate a teenager's mind:
Finding
a boyfriend or girlfriend and finding a way to make a living. The
way these needs are expressed can range from trying to have sex with
whomever
will have you and making, borrowing, or stealing enough money to make a
good showing, to a serious effort at creating the foundation for a
lifelong
partnership based on love and training for a financially and
personally rewarding career.

The end of adolescence is as much a social
thing
as a physiological thing, so it is very hard to say when that is, but
in
western cultures, we usually think of 18 as a convenient mark.
But, with work and family delayed as long as they are nowadays, a lot
of the
traditional tasks of adolescents continue well into the 20's.

Because the adolescent is in the process of breaking away from his
or
her parents, there is often conflict between them. Ideally,
adolescents
acknowledge their parents wisdom and politely leave the house, while
parent
trust their children to make their own decisions and let them go.
Unfortunately, it often doesn't work that way. It is almost as if
nature is making us so repugnant to each other that we are absolutely
eager
to go our separate ways.

These conflicts between parents and their adolescent children go
back
many generations. Socrates and other Greek philosophers
complained
about this upcoming generation of spoiled slackers, as did writers in
the
renaissance and all the centuries. Here's a paraphrase of one
such
complaint:

"Where did you go?"
"I did not go anywhere."
"If you did not go anywhere, why do you idle about? Go to
school...
Do not wander about in the street.... Don't stand about in the
public
square or wander about the boulevard.... You who wander about in
the public square, would you achieve success?... Because my heart
had been sated with weariness of you, I kept away from you and heeded
not
your fears and grumblings.... Because of your clamorings... I was
angry with you.... Because you do not look to your humanity, my
heart
was carried off as if by an evil wind. Your grumblings have put
an
end to me, you have brought me to the point of death."

This is a piece of a conversation between a Sumerian youth and his
father,
recorded in cuneiform some 3 or 4 thousand years ago. (From S. N.
Kramer, The Sumerians, University of Chicago Press,
1963.)
Funny, I could have sworn I heard this conversation just the other day!